Since emulating a CPU is a fairly memory intensive thing to do,
it's unlikely that the Z-80 emulator code will require any reworking
to fit your needs. There is an option you need to set, though. Two
files are included to handle I/O instructions. io_mem.c implements
a 256 byte RAM on the I/O space. io_ask.c prompts the console
for input and prints output writes.

You also have a couple choices for main():

debug.c is a debugger.

dumbrun.c pre-loads either a binary file or a HEX file into Z-80 memory
and jumps to the first byte. io_ask.o is the recommended I/O here,
otherwise there will be no way to see any results of running your
program.

upm.c implements CP/M on top of the emulator. See README.upm

There are two things to know before starting:

The math operations assume that "!=" "returns" 0 or 1. A bad
assumption, to be sure. If this assumption is not true for your
compiler, find all occurances of "alu_" in the code and examine
them.

Some compilers have trouble dealing with signed chars. This causes
the JR code some grief. If this is a problem, change the define
for DO_JR in z80.h as necessary.